1. Field of the Invention
The present invention relates to an image forming apparatus which is configured to fix a toner image on an envelope.
2. Description of the Related Art
Hitherto, an image forming apparatus employing an electrophotographic system, such as a copying machine and a printer, has been configured to fix a toner image on an envelope, onto which the toner image is formed by an image forming portion, by conveying and heating the envelope with use of a fixing device. After that, in the image forming apparatus, the envelope is nipped by a pair of rotary members, and is conveyed by the rotation thereof. When the envelope is heated by the fixing device, the moisture in the envelope often evaporates.
A water-soluble adhesive is often applied to the flap (flap part) of the envelope. Therefore, when the envelope is heated by the fixing device, the moisture of the envelope may evaporate, and the adhesive applied to the flap may dissolve by the evaporated moisture. When the envelope is nipped thereafter by a conveying roller or the like, the flap may stick to the envelope main body.
There is known an image forming apparatus including a flap releasing mechanism for forcibly separating the flap from the envelope main body in order to prevent the flap from sticking to the envelope main body (Japanese Patent Application Laid-Open No. H05-94067).
The flap releasing mechanism of the conventional image forming apparatus has a certain size, and is provided at a position at a distance from the fixing device. Therefore, the flap releasing mechanism often peels off the flap after the flap is stuck to the envelope main body, and thus the envelope is damaged in some cases.